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How to Fix a Leaking or Running Toilet

Toilet won't quit running

How to Fix a Leaking or Running Toilet

Have you noticed an increase in your water bill or found water on the floor around your toilet? It’s likely that your toilet is either leaking or running continuously. Here’s how to identify and fix the issue with standard, floor-mounted toilets.

Identifying a Running Toilet

  1. Remove the Tank Lid: Carefully take the lid off the toilet tank and set it aside. Inside the tank, you’ll find the fill valve on the left side. There are several types of fill valves:
    • Vertical Riser with a Cylinder: This type has a cylinder that slides up and down the riser, with a vertical lever that adjusts the water level and shuts off the valve when it reaches the desired height.
    • Vertical Riser with a Long Arm: This type has a long arm reaching to the right side with a large float on it. Adjust the water height by slightly bending the arm or turning the screw at the base of the arm.
    • Shoe-Like Fill Valve: This type’s water height adjustment involves unlocking the riser, twisting it, raising or lowering the entire unit, and then re-locking it.
  2. Listen for Hissing Sounds: Place your ear near the tank. If you hear a slight hissing sound, it means water is escaping from the fill valve, indicating it’s not shutting off completely. This could be due to one of the following:
    • High Water Level: If the water level is at the top of the flush valve and you hear hissing, the fill valve might be faulty. Compare with other toilets in your house. If they don’t have the same issue, you likely need to replace the fill valve. If multiple toilets are affected, it could be a house-wide pressure issue. Check the pressure at an outdoor spigot; if it’s over 75 psi, that could be the problem.
    • Debris in the Fill Valve: Rust or debris from galvanized pipes can wear out the rubber gaskets in the fill valve, causing leaks. In this case, replacing the fill valve is necessary. You can find instructional videos on YouTube for guidance.
  3. Check the Water Level: If the water level is below the top of the overflow tube on the flush valve but the fill valve is still hissing, the issue is likely with the “flapper” or disc. Flappers can be either generic or specific to your toilet model.
    • Replacing the Flapper or Disc: Shut off the water, remove the worn flapper or gasket, and take it to a hardware store to get an identical replacement. Install the new part and turn the water back on.

Addressing Water on the Floor

  1. Check for Toilet Movement: Gently rock the toilet from side to side and try lifting it slightly from the front. If the toilet moves, the wax seal to the flange has likely failed, and the toilet needs to be reseated.
  2. Inspect the Tank and Bowl Connection: Feel behind the toilet where the tank meets the bowl. If the porcelain is wet, it might be the tank-to-bowl gasket or the bolt washers. These can be replaced with new gaskets and washers.
  3. Examine the Supply Line and Shutoff Valve: If the supply line is wet, it might need to be replaced, or the fill valve might not be tight enough. If only the shutoff valve is wet, tighten the bonnet nut or the supply line. Dry everything off and check again after 30 minutes. If it’s still wet, replace the valve and the supply line.

Why Consider Hiring a Plumber

While many toilet repairs can be done by a handy homeowner, there are several reasons you might want to hire a professional plumber:

  1. Expertise and Experience: Plumbers have extensive training and experience, ensuring that they can quickly diagnose and fix issues that might be challenging for a DIYer.
  2. Time-Saving: If you’re not familiar with plumbing repairs, troubleshooting and fixing a toilet issue can be time-consuming. A plumber can resolve the problem efficiently, saving you time and hassle.
  3. Proper Tools and Equipment: Professional plumbers have the right tools and equipment for the job, which can make repairs more effective and long-lasting.
  4. Avoiding Further Damage: Incorrect repairs can lead to more significant issues, including water damage to your home. A plumber ensures the job is done correctly the first time, reducing the risk of additional problems.
  5. Warranty and Guarantees: Many plumbers offer warranties on their work, giving you peace of mind that if the problem recurs, it will be addressed without additional cost.


Fixing a leaking or running toilet can save you money on your water bill and prevent damage to your home. By identifying the source of the problem and following these steps, you can resolve many common toilet issues yourself. However, for more complex repairs or if you’re unsure about any steps, consider consulting a professional plumber. Their expertise, tools, and guarantees can provide a reliable and long-lasting solution.

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